Easy-open containers are used today to package virtually thousands of products, most notably beverages. An example of a particularly popular easy-opening system, which is commonly referred to as a "tape tab", utilizes a heat sealable strip of tape to seal a pre-cut dispensing aperture in the container's top end panel or lid. Early embodiments of this general concept are disclosed in U.S. Pat. No. 2,870,935 issued to Houghtelling, U.S. Pat. No. 3,186,581 issued to Schneider et al., and U.S. Pat. No. 3,251,515 issued to Henchert et al.
Easy-open containers employing the above-described tape tab have thus far met only limited success in the marketplace. A major problem associated with such a system is providing a gas and liquid impermeable seal between the tape and the outer surface of the container's lid. Another serious problem associated with such a system is the exposure of the aperture's raw edges to the product inside the container. One proposed solution to these problems is to cover the dispensing aperture with another discrete tape from the inner surface of the container's lid. An example of this "two-tape" system is disclosed in U.S. Pat. No. 3,339,788 issued to Lipske. While this two-tape system does appear to insulate the aperture's raw edges from the product, the gas and liquid impermeable seal problem is still present, i.e., this critical seal between the tape and the lid is merely moved from the lid's outer surface to the lid's inner surface. Furthermore, the cost of using two discrete tapes is undoubtedly much more expensive than using one. Other examples of this two-tape system are found in U.S. Pat. No. 3,355,059 issued to Balocca et al. and U.S. Pat. No. 3,990,603 issued to Brochman.
Returning to the single tape system, an improved means to obtain the critical seal between the tape and the container's lid has been suggested in U.S. Pat. No. 4,116,359 issued to Josephy. According to Josephy, a localized portion of a laminated tape having a bottom plastic layer is first extruded through the lid's aperture. Then, the plastic layer is radially outwardly squeezed around the aperture on the inner surface of the end panel, thereby providing the necessary critical seal. However, in a high-speed manufacturing setting, such a process would be incredibly expensive and slow. In addition, a laminated tape of the type found in Josephy is much more expensive to make than a single layer tape.
Another similar proposal to overcome the difficulties associated with utilizing a single tape tab to seal a dispensing aperture is disclosed in U.S. Pat. No. 3,338,462 issued to Reynolds et al. The proposal essentially consists of applying a laminated tape tab having a top layer of aluminum and a bottom layer of plastic in overlying relation to the pre-cut aperture, followed by applying heat and an anvil from the bottom surface of the lid to form what is call a "molded-in-situ" plug. When molded, this plastic plug seals the dispensing aperture and also acts as a protective coating around the aperture's exposed metal edges. Although Reynolds' system appears to be capable of sealing the aperture, it is also too complicated and difficult to practice on a high-speed manufacturing level because of the precise registration required between aperture, tape, plastic plug, and anvil. In addition, the laminate tape as described is also relatively expensive to make.
Another shortcoming of virtually all of today's easy-open containers is the inability to reclose the container after the initial opening thereof to preserve the container's contents and also to prevent foreign matter from entering the container during storage. In addition, if the container's contents includes suspended solids such as fruit pulp, most easy-open containers cannot be reclosed and shaken to redistribute such solids. An example of an easy-open container that does provide reclosing means is found in U.S. Pat. Nos. 4,164,303 and 4,232,797, both issued to Waterbury. These patents disclose several embodiments of an articulated closure element that is hingedly mounted on the container's lid adjacent to a pre-cut dispensing aperture. The closure element has a depending plug or bead on its undersurface that is shaped complementary to the aperture. After the closure element is lifted to initially open the container, the container may be reclosed by returning the closure element back to its original position such that the depending plug or bead engages the dispensing aperture.
Although Waterbury's articulated closure element system does allow an easy-open container to be reclosed after initial opening, the system requires a critical seal between the closure element and the container's lid very similar to that associated with tape tab systems as described earlier. Waterbury suggests that this critical seal can be achieved by thermoformation, i.e. applying heat to the lower edge of the thermoplastic closure element to cause the material to flow outwardly underneath the lid surface. Alternatively, Waterbury suggests that the depending plug or bead may be eliminated altogether and a plastic coating applied across the aperture from the lid's inner surface. However, eliminating the plug or bead and using this "inner patch" seal would presumably destroy the ability to reclose the container. In any event, a fair reading of Waterbury suggests that obtaining a critical seal between the closure element and the dispensing aperture is difficult to achieve, particularly if an aseptic seal is initially required.
Another problem associated with easy-open containers, particularly those having an upstanding rim about the periphery of the container's top lid, is that a residual amount of product is inevitably trapped between the dispensing aperture and the container's upstanding rim when the container is tipped to dispense the container's contents. When the container is returned to its upright position, this residual tends to spread out over the lid's surface and, during storage, begins to collect dirt and dust. Furthermore if the beverage is sweet such as a fruit juice, the residual attracts insects.
Another problem found in most easy-open containers is the failure to use suitable materials that simultaneously provide strength, oxygen impermeability, and protection against flavor loss of the container's contents.
In light of the above, it is a principal object of the present invention to construct a laminated easy-open container from materials that provide strength, oxygen impermeability, and protection against flavor loss.
Another principal object of the present invention is to eliminate the need for a gas and liquid impermeable seal between an easy-open container's opening means and the container's dispensing aperture.
It is another principal object of the present invention to provide an easy-open container with a relatively inexpensive easy-opening means that does not have to be made from materials having special properties such as gas impermeability or beverage-contacting compatibility.
Another principal object of the present invention is to provide an easy-open container with reclosing means.
It is another principal object of the present invention to eliminate the need for a gas and liquid impermeable seal between a container's easy-open/reclosing means and the container's dispensing aperture.
It is another principal object of the present invention to provide an easy-open container with a relatively inexpensive reclosing means that does not have to be made from materials having special properties such as gas impermeability.
It is another principal object of the present invention is to provide an easy-open container with a lid configuration that substantially reduces the tendency of the container's contents to spread out over the lid's entire outer surface after a portion of the container's contents have been dispensed.
Another object of the present invention is to provide a low cost, high speed method of making an easy-open or an easy-open/reclosable laminated container.